One more way that Japan would have been better off not to have started the war at all.
True, but they're stuck. The IJA has gone rogue in China, first ignoring and then replacing the government. The country's military spending is now over 40% of GDP, and food and materials are running out. They're painted into a corner and getting desperate, with no facing saving way out. It's too bad that China didn't kick their ass in 1937-38 and thus put the IJA in their place at home.
But if Japan could find a honourable exit from China, an end to US and British sanctions, and reduced military spending to about 10% (Britain never exceed 5% pre-war) it would have been interesting to see the smaller, and presumably sharpened Kido Butai, IJNAS and IJAF.
I'd expect the small and slow carriers Hosho and Ryujo to be mothballed and eventually scrapped, and the two
Junyo class not to be converted to carriers, and the six
Unryu class fleet aircraft carriers canceled in place of additional Taiho armoured fleet carriers, with the first two replacing a retiring Kaga and Akagi. Shinano is canceled, the two Yamatos complete as battleships. On aircraft, A5M and Ki-27 are retired.
Diplomatically, as a buffer to the US and USSR, Japan needs to enter the war close to Britain. And if they play their cards right, Japan can hold onto Korea and maybe Manchuria into the 1950s and beyond.